The finite element analysis of polyetheretherketone/hydroxyapatite/carbon fiber cage / 生物医学工程学杂志

To compare the bio-mechanical characteristics of cages of two types, i. e., polyetheretherketone/ hydroxyapatite/carbon fiber (PEEK/HA/CF) and titanium combined with internal pedicle screw fixation in lumbar model, and to provide experimental evidences for clinical application, we constructed a three-dimensional finite element model of an intact L2-L4 segment by using computer tomography scans of a healthy male. The three-dimensional finite element models of an intact L2-L4 segment and single cage plus bilateral vertebral pedicle screw fixation were established. The angular motion of fused segment and stress distribution in the bone graft and cage and L3 inferior endplate under different loads were recorded. The result showed that the peak Von Mises stresses of the bone graft of PEEK/HA/CF group were at least 2.2 time as that of titanium group. The peak Von Mises stresses of L3 inferior endplate of the titanium group were at least 2. 3 times as that of PEEK/HA/CF group. These stresses were concentrated at places where the cage interfaced with the endplate. The angular variation of the titanium group showed similarity to PEEK/HA/CF group. The PEEK/HA/CF cage could provide stability similar to that of titanium cage in the presence of posterior instrumentation. It could increase the load transfer through the bone graft and promote the bone fusion. It could also reduce the stresses in endplates adjacent to the cage and reduce the subsidence of the cage.

Research on the extracorporeal cytocompatibility of a composite of HA, carbon fiber and polyetheretherket-one / 生物医学工程学杂志

The present research was to study the biocompatibility of a composite of hydroxyapatite (HA), carbon fiber (CF) and polyetheretherket-one (PEEK) by co-culturing with the osteoblasts in vitro. Cell relative growth (RGR) was used as a quantitative assessment for cytotoxicity of the biomaterials by CCK-8. The proliferation index of the co-cultured cells and ALP activity was measured to study the effect of PEEK-HA-CF composites. Morphological properties of the osteoblast cells in vitro were observed by scanning electro-microscopy (SEM). The PEEK-HA-CF materials have no cytotoxicity to osteoblasts. The proliferation index of PEEK-HA-CF was higher than that of Ti alloy group, but these was no significant difference compared to that of control group. The ALP activity was the highest on PEEK-HA-CF composites surface after 7 days. The osteoblast cells co-cultured with the PEEK-HA-CF composite were adhered well to the biomaterial as observed under the SEM. The results suggested that the PEEK-HA-CF composites had good biocompatibility in vitro and might be a novel orthopedic implanted material.